Here the camera has focused on the jacket or possibly the body, not the dog's head. Now it is possible with any single shot that that is user error, but not in EVERY case. All afternoon, the camera ignored the dog's head, despite it largely filling the focus point, and got the background instead.Intensely annoying.

At 100%, I can't see anywhere that I would call sharp and certainly not the jacket. The best I can find is the fabric on the guy's right ankle. If that were the case, the focus is way in front of the subject. The only way I can think of to get this happening would be to have Release Priority for S-AF set to On. That would allow the shutter to fire before focus is acquired.